1. Field of the Invention
The invention relates to the beneficiation of ores, especially phosphate ores. In a particular aspect the invention relates to flotation of phosphate ore from siliceous materials with agents comprising a combination of sulfonated hydrocarbon and a petroleum fraction.
2. Description of Prior Art
Phosphate ore is found in various places in nature, and it contains a valuable raw material for producing many products, principally fertilizer. The most useful constituent of the ore is calcium fluorphosphate; those of no value include calcium carbonate, carbonaceous materials, heavy minerals and siliceous materials such as silica. Removal of these valueless materials is necessary and has been the subject of extended research.
As taught in U.S. Pat. No. 3,817,972, partial concentration is first employed to remove slimes and this is followed by two separate beneficiation steps. The first one is the fatty acid flotation of phosphate values using an acid and caustic in combination with a petroleum fraction such as kerosene. The fraction obtained, or rough concentrate, still contains considerable siliceous material which is treated in a second flotation using long chain fatty acid amines or salts thereof.
U.S. Pat. No. 3,292,787 discloses that in a process for beneficiating phosphate ores by flotation, one may use a sulfonated aromatic hydrocarbon in the molecular weight range of 400 to 500. The sulfonated material is used at a concentration of at least 0.1 pound per ton in the presence of a hydrocarbon oil.
Other U.S. patents disclosing the use of sulfonated hydrocarbons in ore recovery processes are U.S. Pat. Nos. 2,069,182 and 2,442,455. None of the patents mentioned suggest or teach the fact that such extremely small amounts of sulfonated hydrocarbons and kerosene will be effective in recovery of phosphate values.